简介:Purpose:Thepurposeofthisstudywastoinvestigatetheeffectofvariableintensitiesonasimplememoryrecognitiontaskduringexercise.Methods:Twentyactiveparticipantstookpartininitialtesting,afamiliarizationtrialandthenfour60mincyclinginterventionsinarandomizedorder.Interventionsconsistedofnoexercise(control),constantexerciseat90%ventilatorythreshold(constant)and2trialsthatinitiallymimickedtheconstanttrial,butthenincludedperiodsofhigh(90%VO2peak)andlowintensities(50%VO2peak).Cardiorespiratorymeasuresandcapillarybloodsamplesweretakenthroughout.Ashorttablet-basedcognitivetaskwascompletedpriortoandduring(50and55minintoexercise)eachintervention.Results:Theexerciseconditionsfacilitatedresponsetime(p=0.009),althoughtheextentofthiseffectwasnotasstronginthevariableexerciseconditions(p=0.011–0.089).Highintensityexerciseperiodsresultedinsomecognitiveregressionbacktowardscontroltrialperformance.Elevationsincardiorespiratorymeasuresandperiodsofhypocapniacouldnotexplainchangesincognitiveperformance.Conclusion:Changesincognitiveperformancewithvariationsinexerciseintensityarelikelytohaveimplicationsforsportandoccupationalsettings.Thetimingofcognitiveteststoexerciseintensitychangesaswellasuseofshortcognitiveassessmentswillbeimportantforfuturework.
简介:Purpose:Thepurposeofthisstudywastocomparethecoordinationbetweenthetrunkandthepelvisduringasustainedasymmetricrepetitiveliftingtaskbetweenagroupwithahistoryoflowbackpain(LBP;HBP)andagroupwithnohistoryofLBP(NBP).Methods:Volunteerslifteda11-kgboxfromankleheightinfronttoashelf45°off-centeratwaistheight,andloweredittothestartpositionat12cycles/minfor10min.Liftingsidewasalternatedduringthetrial.Continuousrelativephasewasusedtocalculatecoordinationbetweenthepelvisandtrunkrotationatthebeginning(Min1),middle(Min5),andendofthebout(Min9).Results:Whiletherewerenomaineffectsforgroup,asignificantinteractionbetweentimeandgroupindicatedthat,inthefrontalplane,theNBPgroupcoordinationwasmoreanti-phasetowardtheendofthebout,withnosuchdifferencesfortheHBPgroup.Analysisofsagittal-axial(bendandtwist)coordinationrevealedtheHBPgroupcoordinationwasmorein-phaseattheendoftheboutovertheentirecycleandfortheliftingphasealone,withnosuchdifferencesfortheNBPgroup.Conclusion:DifferencesbetweengroupsdemonstrateresidualconsequencesofLBPinanoccupationalscenario,eventhoughtheHBPgroupwaspain-freefor>6monthspriortodatacollection.Morein-phasecoordinationintheHBPgroupmayrepresentacoordinationpatternanalogousto'guardedgait'whichhasbeenobservedinotherstudies,andmaylendinsightastowhytheseindividualsareatincreasedriskforre-injury.
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